Theoretical model for enrichment ofCH3Fnuclear-spin isomers by resonant microwave radiation

Abstract

A theoretical model of coherent control of nuclear-spin isomers by microwave radiation has been developed. The model accounts the M degeneracy of molecular states and molecular center-of-mass motion. The model has been applied to the 13 CH 3 F molecules. Microwave radiation excites the para state (Jϭ11, Kϭ1) which is mixed by the nuclear-spin-spin interaction with the ortho state ͑9,3͒. Dependences of the isomer enrichment and conversion rates on the radiation frequency have been calculated. Both spectra consist of two resonances situated at the centers of nuclear-spin-allowed and -forbidden transitions of the molecule. Larger enrichment, up to 7%, can be produced by strong radiation resonant to the forbidden transition. The spin conversion rate can be increased by two orders of magnitude at this resonance.